Automotive electrical system



June 26, 1951 E. M. cLAYToR 2,558,644

AUTOMOTIVE ELECTRICAL SYSTEM Original Filed May l2, 1948 IN1/MMR. Hiv/4m? H. M2/T01? Patented June 26, 16951 UNITED ST-A'li YAP'ENT OFFICE AUTOMOTIVE ELECTRICAL SYSTEM Edward M. Claytor, Anderson, Ind., assignor to General Motors Corporation, Detroit, `Mich., a corporation of Delaware Original application May `12, 1948, Serial No.

Divided and this application August 18, 1950, Serial No. 186,699

(Cl. S20-.50.)

1 Claim.

ing I2 comprises a lesser number of turns of relatively iine wire whereas the main winding II comprises a greater number of turns of relatively coarse wire. For example, winding II may have 452 turns of #17 wire and Winding I2 may have 195 turns of #31 Wire. The output terminals of the generator are marked I, 2 and 3. These terminals may be indirectly connected through a transformer t!) or may be directly con- Serial No. 26,690 iiled May 12, 1948. in nected with the input terminals Ir, 2r and 31" re- An object of the invention as claimed in this spectively of a rectier I3 having D. C., output application is to obtain adequate direct current terminals 51' and Er connected respectively with at low engine speeds when the A. C. voltage is so wires 5 and 5. Wire 8 is connected directly with W that the rectifier voltage is insuificient for the negative terminal of a storage battery I4 and battery charging and other purposes. In the disi5 Wire 5 is connected With battery positive ter- `closed embodiment thereof, the present invention minal through a relay I5 having a contact IE conprovides a transformer in the circuit between the nected with wire 5 and engageable by a contact Il generator and rectifier so as to step up the voltage carried by an armature I3 connected Aby a spring so that the rectifier voltage Will be suflicient at hinge i9 with a frame 20 attached to the core 2l low input speeds, and provides for disconnecting gi) which is surrounded by windings 22 and 23. the transformer and for connecting the generator Winding 22 S connected across wires 5 and 6. directly with the input terminals of the rectiiier Winding 23 is connected with the frame of the when the generator is operating in the higher relay and hence with the contact I'I and with the speed-range, positive terminal of the storage battery. When A further object of the invention as claimed 25 the voltage across the coil 22 exceeds the batin application Serial No. 26,690 is to make postery counter voltage, armature I8 will move sible the use of a eld magnet core made of comdown to cause contact I'! to engage contact IS mercial grades of iron having residual magnetism whereupon current will flow to the battery which will enable the eld magnetism to be built through the Winding 23 which maintains the up without the use of a separate field exciting contacts of the relay closed while the battery is generator, The invention provides a reverse field being Charged. When the Output Voltage 0f the which opposes residual magnetism and effects rectier I3 falls below the counter voltage of the reduction of the resistance value of the iield regbattery, the battery will begin to discharge ulator when the generator is operating at high through the coil 23 thereby creating a magnetism speeds. which counteracts that created by the coil 22 `and Further objects and advantages of the present the relay I5 Opens. Other load ClCutS may be invention will be apparent from the following connected with the wires 5 and 6. While the batdescription, reference being had to the accomtery iS fully Charged, it is said to oat on the panying drawings, wherein a preferred embodiline. ment of the present invention is clearly shown. i0 The I0-lling@ Output Of the generator `iS klimited In the drawing: by a carbon pile voltage regulator 39 which com- The figure of the drawing is a Wiring diagram prises a stack of power consuming carbon disc 0f an embodiment of the present invention 3i lccated between a fiXed electrode 32 and a A 3-phase A, C, generator ig having a main movable electrode 33 connected with an armature D. C. eld exciting Winding Il and an auxiliary ,i5 35i which is adjacent a core 35 surrounded by a bucking or reverse Winding I2 is driven at vari coil connected between wires 5 and 6. Spring able speed by the Vehicle propelling engine. 3l' urges the electrode 33 toward the electrode These eld windings excite a eld magnet core 32, thereby placing the pile 3| under compression II2 made of commercial grade of iron having so that its resistance will be least when the residual magnetism in order that the eld mag- 5G SllSl'gZ-vol 0f the COil 35 is least. The main netism can build up Without requiring the use of a separate field exciting current source. Since a function of the winding I2 is to counteract full excitation at higher speeds but not to interfere with residual magnetism at low speed, wind- 3 zero to a value at which regulation begins, current in winding II increases to a relatively high value and current in winding I2 increases to a value lower than in winding II because the resistance of winding I2 is much higher than the resistance of winding II. The opposing flux produced by winding I2 is insuicient to prevent the starting of self excitation of the generator field with the aid of residual magnetism. At the generator speed at which the regulator B beings to function, the maximum current value in winding II is attained. The regulator 5B is set for some voltage above the battery counter voltage when fully charged. If the battery is a l2-volt battery, the voltage regulator might be set for 14 volts for example. When the voltage on coil 36 begins to exceed 14 volts, the bias of the spring 3l is overcome by a negative pull on the armature 3d; the pressure between the discs of the carbon pile decreases, and its resistance increases, thereby decreasing the current flowing through the field winding I i. As speed increases above the value at which the regulator 53 begins to function, current in the winding il is caused to decrease by the regulator in order to reduce field excitation so that the voltage across the rectified output terminals will be maintained at the Value for which the regulator is set, for example lli volts. Since current in the winding I2 continues at the value which corresponds to the voltage across the rectifier output terminals, the winding I2 continually provides a bucking ux which reduces field excitation. Therefore regulator is not required to reduce current in winding Ii to the extent that would be necessary if the winding I2iwere not present. Since the resistance required to be introduced by the pile 3l is less than without the winding I2, closer regulation can be effected in the higher speed range, and the life of the regulator is increased.

In the low speed range, the output of the generator might be at a voltage weil below that which would enable the rectifier to put out a voltage sufficient for the battery charging and other purposes. In order that sufcient voltage may be supplied to the rectifier from the generator in the low speed range, the direct connections between the generator and rectifier input terminals are interrupted and a step-up transformer 4S is inserted. The transformer d@ has Y-connected primary windings pi, 2 and p3 and Y-connected secondary windings 5I, s2 and s3. Primary pI is connected to generator terminal i by contacts pci and pci of a relay to be described. Secondary si is connected with rectifier terminal I1' by contacts sci and sci. Primary p2 is con nected with generator terminal 2 through contacts pc2 and pc2. Secondary s2 is connected with rectified terminal 21' through contacts 8c2 and SC2. Primary p3 is connected with generator terminal 3 through the contacts p03 and ps3.

Secondary s3 is connected with terminal 31' through contacts 8c3 and SC3. The contacts, which are used to connect in the windings of the transformer between the generator and the rectifier as stated, are known as the bach contacts of a relay which has an armature 5I which insulating-ly supports all of the contacts pci sci', pc2', co2', pc and sci. The contacts normally engaged by the armature supported contacts are mounted on a fixed support of the relay. The relay armature 5i is connected by a spring hinge 52 with a frame 53 connected with a core surrounded by a winding 55 connected at one with wire 6 and at the other with wire 5 by closure of contacts I6 and I1 of relay I5 and by closure of contacts 6l and 62 of a speed responsive switch 60 which includes a lever 63 pivoted at 64 and caused to move clockwise by operation of a ily-ball device driven by a shaft SB connected with the rotating generator armature. Contacts 6I and B2 are caused to engage when generator speed reaches a certain value. The spring hinge 52 of relay 50 biases the armature 5I upwardly. Although the armature 5I is shown in three places, it is in fact one member as the dot-dash line EIL indicates. In the low speed range of the generator coil 55 is not energized so that the transformer 4U will be connected between the generator and the input terminals of the rectifier I3. The rectifier output voltage will become sufficient for battery charging at a speed which is lower than would be the case if the transformer 4B were not provided. At some speed in the higher speed range corresponding to which rectifier output voltage would be excessive, if not regulated, the contacts QSI, 62 of switch Si? are closed. Contact I6, il of relay i5 being closed, coil 55 is energized and the armature El moves down to separate the transformer connecting contacts and to engage other pairs of contacts which connect the generator terminals I, 2 and v3 directly with the rectifier input terminals Ir, 2r and 3T i'espectively. The pairs of contacts for making the direct connections are marked respectively di, dl and cl2, d2 and d3 and d3. The contacts designated by the primed numbers are inN sulatingly supported by the armature 5I and the others are fixed to a stationary support. There being a momentary reduction in the A. C. voltage applied to the rectifier input terminals and consequent reduction in D. C. output voltage of the rectifier, the regulator Sil will immediately operate to reduce resistance o-f pile SI in order to increase current in winding II so that the generator voltage will immediately increase to such value that the rectifier output voltage is suificient for battery charging.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claim which follows.

What is claimed is as follows:

An electrical system comprising a variable speed A. C. generator having field windings, a rectifier having A. C. input terminals connected with the generator input terminals and having D. C. output terminals connected with the field windings, means for regulating eld current, a step-up transformer having primary and secondary windings, a relay switch normally directly connecting the primary windings of the transformer with the generator output terminals and the secondary windings of the transformer with the A. C. terminals of the rectifier, said relay switch having an electromagnet the energiaation of which causes the relay to opencircuit the transformer and to connect the generator output terminals directly with the rectifier output terminals, a storage battery, a relay switch for connecting the rectifier output terminals with the battery when the rectier output voltage is sufficient for battery charging, and an energizing circuit for the electromagnet of the first mentioned relay switch and including, in series, the rectifier output terminals, the second 5 A 6 mentioned relay switch and a switch which closes Number Name Date in response to attainment of a, certain generator 763,168 Entz June 21, 1904 speed. 1,475,880 Ricketts Nov. 27, 1923 EDWARD M. CLAYTOR. 1,784,308 Neuland Dec. 9, 1930 5 1,960,683 Strong May 29, 1934 REFERENCES CITED 2,099,468 Cerstvik Nov. 16, 1937 The following references are of record in the 2,208,416 Fiedlander et a1- July 16 1940 fue of this patent; 2,335,167 Zlerdt Nov. 23, 1943 UNITED STATES PATENTS lo FOREIGN PATENTS Number Name Date Number Country Date 402,192 Prescott, Jr Apr. 30, 1889 27,636 Great Britain Dec. 17, 1904 418,748 Prescott, Jr Jan. 7, 1890 683,860 France Mar. 19, 1930 

